There has been known an adsorber in which an adsorption part filled with an adsorbent, which adsorbs and desorbs an adsorption medium (for example, water), and an evaporation/condensation part (heat exchanger), which exchanges heat between a heating medium supplied from the outside and the adsorption medium to thereby evaporate or condense the adsorption medium, are provided in a closed container which is held in a state nearly close to a vacuum (for example, refer to Patent Document 1). In this kind of adsorber, the adsorption medium of a liquid phase is evaporated by the evaporation/condensation part in the closed container to thereby obtain a refrigeration capacity by a latent heat of evaporation and the adsorption medium, which is evaporated to be brought into a vapor phase, is adsorbed by the adsorbent in the adsorption part to thereby accelerate evaporation, which results in continuously exerting the refrigeration capacity.